Installation for measurement and display of a fluid volume and corresponding use to keep valves and metering equipment frost free and accessible.
This invention relates to an installation for measurement and display of a fluid volume protected against risks of frost.
More particularly, the fluid volume measurement and display installation comprises a fluid metering assembly such as water, gas or fuel connected to a fluid inlet pipe and a fluid outlet pipe.
In known installations for measuring fluid volumes protected against risks of frost, the water meter is located either below ground level or in a chamber.
The ground acts as thermal insulation below a given depth. Only the top part is frozen in winter. This top part isolates heat in the lower part of the ground from the cold. In France, this thermal insulation is achieved after 15 days frost at a temperature of xe2x88x9215xc2x0 C., starting from a depth of forty-five cm in the ground. Known chambers are preferably closed at the top by a removable cover to access the meter.
In all cases, the meter and fluid inlet and outlet pipes have to be protected against risks of frost.
Various techniques have been proposed for this purpose.
When the meter is above ground level, it is known how to protect it on the outside by a box, or a tank or similar system. This type of box must enable access to the meter.
According to one of these techniques, it has been proposed to protect the metering assembly by heat ducts buried in the ground and put into a condition for heat exchange.
According to another known technique, it is proposed to coat the inside of the chamber into which the water pipes lead, and the inside of the containment in which the meter is located, by elements made of an insulating material such as expanded polystyrene or polyurethane foam.
American patent U.S. Pat. No. 3,802,266 discloses a water meter with a bottom with a special shape for frost protection.
French patent 87 03453 presents a water meter installed free to pivot on a base comprising two water passages, connected to the water inlet and outlet pipes respectively. With this arrangement, the fluid inlet can be opened and closed by rotating the meter with respect to the base to bring the fluid passages in the base into line with the fluid passages in the meter, or to move them out of line.
It is known that an additional device can be added to drain the fluid, for example French parent No. 2749920 discloses a device consisting of a cylinder with two horizontal drillings (top and bottom) connected to each other through a vertical drilling in its axis, which is inserted into its valve body, the valve body itself is perforated around its circumference at its four cardinal points, in other words four times at 90xc2x0 intervals, two high points, North-East, North, outlet at East, and drain outlet, two low points South-West, South, inlet at West and drain. The assembly will be actuated using a control on the surface. In the winter position, the action will be simultaneous open, close and drain of the riser. This known device is designed particularly for the cut-off valve following the water meter.
However, the use of these frost free protection means is complicated and consequently expensive.
Furthermore, in these designs in which the meter is above ground level, thermal bridges remain between the meter and the outside so that frost protection is not complete.
In the second case, when the meter is buried sufficiently deep below ground level, it is efficiently protected against frost. But other difficulties have to be overcome. It is necessary to go down into the chamber to access the meter, either to read the volume consumed, or for maintenance, to inspect the meter and parts of valves such as the non-return valves, the water sample taker for analysis and to install and check the anti-fraud system.
The purpose of the invention is firstly an installation protected against frost risks in which the fluid volume can be measured and displayed easily and quickly, while also avoiding frequently going down into a deep and narrow chamber. The invention simplifies the installations while maintaining frost free efficiency with the fluid metering assembly installed in a chamber that may or may not be thermally insulated at a frost free depth. Fluid pipes extend into a trench made in the ground and are connected to the chamber that has an upper opening closed by an inspection cover. Installation under pavements imposes small chambers. Some pavements themselves are small. In all cases, the installation is controlled by an authorization which is usually only allowed for small chambers. Consequently, the metering assembly can be removed with or without cutting off the fluid under pressure, and may or may not be installed on a meter panel holding the flexible junction means in place connecting the fluid inlet and outlet pipes to the metering assembly, the said flexible junction means being wound and consequently being capable of spreading out inside the chamber with horizontal dimensions slightly greater than the horizontal dimensions of the meter.
Thus, the dimensions of the installation will only be small on the surface. The dimensions visible on the ground surface will be the size of the cover.
To keep the installation effectively frost free while enabling display of the measurement, maintenance and checking of the meter and valve parts such as the non-return valve, the water sample taker for analysis and installation and checking of the anti-fraud system and the flexible junction means can extend at least as far as the top opening of the chamber.
In order to make a shallow chamber, the flexible junction means are flexible connecting tubes wound in the form of at least one turn with a diameter that decreases as the fluid meter is raised. Thus when the metering assembly is in the low position, the tubes do not need a sump below the fluid inlet and outlet.
According to other characteristics:
the flexible junction means are flexible connecting tubes connected to the metering assembly, comprising one or several cut-off means, a meter and a valve that may or may not be guided by a panel and connected to the other ends to the fluid inlet and outlet pipes that may or may not be fixed directly to connectors that may or may not pass through the vertical wall of the chamber;
the metering assembly comprises one or several cut-off means in the form of an angle bracket. These fluid flow cut off means may be either an elbow valve or a straight valve connected to an elbow or an elbow device. The metering assembly also comprises a valve in the shape of an angle bracket, and particularly an elbow or straight valve connected to an elbow fixed by a panel that guides the flexible junction means connected directly or indirectly through elbow connectors to straight connectors. This characteristic makes it possible to place valve elements below the metering assembly; this results in minimum dimensions.
The attachment of flexible junction means to crimped connectors avoids the use of seals and eliminates risks of leaks.
Another purpose of the invention is the use of an installation comprising a fluid metering assembly connected to a fluid inlet pipe and a fluid outlet pipe, this fluid metering assembly being installed in a thermally insulated chamber at a frost free depth, these pipes extending in a trench made in the ground and connected to the chamber with a top opening closed by an inspection cover, characterised in that the metering assembly is removable with or without cutting off the fluid under pressure, that may or may not be installed on a panel holding the flexible junction means connecting the fluid inlet and outlet pipes to the metering assembly, the said flexible junction means being wound and capable of extending within the chamber, and in particular conform with any of the installations described above to keep the standard valve fittings, and particularly straight or coaxial meters, frost free and accessible. This equipment is standard, which simplifies maintenance. Personnel are familiar with this equipment and it is easy to find spare parts.
Other features and advantages of the invention will become clear from the following description.